JP2004163099A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner capable of certainly avoiding abnormal rising of high pressure side pressure of a refrigeration cycle during heating. <P>SOLUTION: When the detected temperature of an indoor temperature sensor 13 becomes a predetermined value or higher and the detected temperature of a temperature sensor 13 of a heat exchanger mounted to the indoor heat exchanger becomes a predetermined value or higher, the abnormal rising of high pressure side pressure of the refrigeration cycle during the heating is certainly avoided by limiting a minimum air quantity of an indoor blower 7 to a predetermined value or higher. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to an air conditioner provided with a heat pump refrigeration cycle capable of cooling and heating.

  A cooling / heating automatic operation mode in which either one of cooling and heating operations is automatically selected and executed, and a normal operation mode in which one of the cooling and heating operations is selectively executed in response to an external request There is an air conditioner having a function and an automatic air volume control function for controlling the air volume of an indoor blower according to a difference between the indoor temperature and a set indoor temperature.

  As for the air volume control, the air volume of the indoor blower is reduced as the indoor temperature approaches the set indoor temperature and the temperature difference becomes smaller.

  Generally, in the cooling / heating automatic operation mode, an energy-saving operation in which the air-conditioning capacity is smaller than that in the normal operation mode is required. However, the air volume control of the indoor blower is the same regardless of the difference between the cooling / heating automatic operation mode and the normal operation mode. Therefore, it is difficult to appropriately control the indoor temperature only by reducing the air conditioning capacity in the cooling / heating automatic operation mode. It becomes.

  The present invention has been made in consideration of the above circumstances, and has as its object to provide an air conditioner that can reliably avoid an abnormal increase in the high-pressure side pressure of a refrigeration cycle during heating.

  The air conditioner of the invention according to claim 1 includes a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an indoor blower having a variable air volume, capable of cooling and heating, and controlling the temperature of indoor air. An indoor temperature sensor for detecting, a heat exchanger temperature sensor for detecting the temperature of the indoor heat exchanger, and a detected temperature of the indoor temperature sensor that is equal to or higher than a predetermined value during heating, and a detected temperature of the heat exchanger temperature sensor that is predetermined. Control means for limiting the minimum air volume of the indoor blower to a predetermined value or more when the value exceeds the value.

  The air conditioner of the invention according to claim 4 includes a refrigeration cycle that connects a compressor, an outdoor heat exchanger, an indoor heat exchanger, and the like to circulate a refrigerant, and is capable of cooling and heating. A heat exchanger temperature sensor for detecting the temperature of the heat exchanger, and a measure for suppressing the high-pressure side pressure of the refrigeration cycle when the detected temperature of the heat exchanger temperature sensor becomes a predetermined value or more during heating. And a control means for setting the predetermined value of the high-pressure protection means to be lower when the temperature detected by the heat exchanger temperature sensor is less than a set value than when the detected temperature is equal to or more than the set value.

  According to the present invention, when the indoor temperature is equal to or higher than the predetermined value and the temperature of the indoor heat exchanger is equal to or higher than the predetermined value during heating, the minimum air flow of the indoor blower is limited to or above the predetermined value, thereby increasing the high pressure of the refrigeration cycle during heating. An air conditioner that can reliably avoid an abnormal increase in side pressure can be provided.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 2, a heat pump refrigeration cycle is mounted on the outdoor unit X and the indoor unit Y.

  Reference numeral 1 denotes a variable capacity compressor, and an outdoor heat exchanger 3 is connected to a discharge port of the compressor 1 via a four-way valve 2 by piping. An indoor heat exchanger 5 is connected to the outdoor heat exchanger 3 via a pressure reducer, for example, an expansion valve 4 via a pipe, and the indoor heat exchanger 5 is connected via a four-way valve 2 to a suction port of the compressor 1. .

  An outdoor blower 6 is provided near the outdoor heat exchanger 3. The outdoor blower 6 circulates outside air through the outdoor heat exchanger 3. In the vicinity of the indoor heat exchanger 5, a variable speed indoor blower 7 is provided. The indoor blower 7 circulates indoor air through the indoor heat exchanger 5.

  The indoor heat exchanger 5 is provided with a heat exchanger temperature sensor 12 for detecting a temperature (condenser temperature) Tc of the indoor heat exchanger 5 during heating.

  An indoor temperature sensor 13 for detecting the indoor air temperature Ta is provided in an indoor air intake air path formed by the indoor blower 7.

  3 and 4 show specific examples of the indoor unit Y. FIG. 3 is a side view of the inside of the housing of the indoor unit Y, and FIG. 4 is a view of the inside of the housing of the indoor unit Y from above.

  That is, the housing 50 of the indoor unit Y is embedded in the opening of the ceiling surface S. The lower surface of the housing 50 is flush with the ceiling surface S, and the lower surface thereof is provided with an air inlet 51 substantially at the center, and a plurality of air outlets 52 are provided at positions surrounding the air inlet 51. Is done. A ventilation space is formed in the housing 50 from the air suction port 51 to each air suction port 52, and the indoor blower 7 (and the indoor blower motor 7M) is provided in the ventilation space. In the ventilation space, the indoor heat exchanger 5 is provided at a position surrounding the indoor blower 7.

  When the indoor blower 7 operates, indoor air is sucked into the housing 50 from the air suction port 51, and is blown into the room from each air outlet 52 through the indoor heat exchanger 5. A filter 53 is provided inside the air suction port 51, and an indoor temperature sensor 13 is attached to an air passage between the filter 53 and the indoor blower 7. A heat exchanger temperature sensor 12 is attached to the indoor heat exchanger 5.

  The control circuit is shown in FIG.

  The indoor control unit 20 of the indoor unit Y is connected to the commercial AC power supply 30. The outdoor control unit 40 of the outdoor unit X is connected to the indoor control unit 20 via the power line ACL and the serial signal line SL.

  The indoor control unit 20 includes a microcomputer and its peripheral circuits. The light receiving unit 21, the speed control circuit 23, the heat exchanger temperature sensor 12, and the indoor temperature sensor 13 are connected to the indoor control unit 20. The outdoor blower motor 7M is connected to the speed control circuit 23.

  The light receiving unit 21 receives infrared light transmitted from a remote control device (hereinafter, simply referred to as a remote controller) 22.

  The speed control circuit 23 controls the speed (that is, the air volume) of the indoor blower motor 7M to another stage. Specific means of the speed control may be any of an AC motor energization phase control, an inverter drive control using a DC motor and an inverter circuit, and a tap switching control.

  The outdoor control unit 40 includes a microcomputer and its peripheral circuits. The four-way valve 2, the inverter circuit 41, and the outdoor blower motor 6M are connected to the outdoor control unit 40. Then, the compressor motor 1M is connected to the inverter circuit 41.

  The inverter circuit 41 rectifies the voltage of the power supply line ACL, converts the rectified voltage to a frequency (and level) voltage according to a command from the outdoor control unit 40, and outputs the voltage. This output is supplied as drive power to the compressor motor 1M.

  The indoor control unit 20 and the outdoor control unit 40 control the air conditioner while mutually performing power supply voltage synchronized data transfer through the serial signal line SL. The following [1] is a main functional means. To [9].

  [1] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the solid arrow shown in FIG. 2, whereby a cooling cycle is formed, and the outdoor heat exchanger 3 functions as a condenser and the indoor heat exchanger 5 functions as an evaporator. A means for performing a cooling operation (and a dry operation).

  [2] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the dashed arrow shown in FIG. 2 by switching the four-way valve 2, thereby forming a heating cycle, turning the indoor heat exchanger 5 into a condenser and the outdoor heat exchanger 3. A means for performing a heating operation by functioning as an evaporator.

  [3] During cooling and heating, the difference ΔT between the detected temperature Ta of the indoor temperature sensor 13 and the set temperature Ts of the remote controller is determined as the air conditioning load, and the output frequency of the inverter circuit 41 (the operation of the compressor 1) is determined according to the temperature difference ΔT. Means for controlling the frequency (F).

  [4] A cooling / heating automatic operation mode operation means for automatically selecting and executing one of the cooling operation and the heating operation.

  [5] Operating means in a normal operation mode for selectively executing either one of the cooling operation and the heating operation in response to an external request by operating the remote controller 22.

  [6] The air flow (that is, the speed) of the indoor blower 7 is controlled according to the difference ΔT between the detected temperature Ta of the indoor temperature sensor 13 and the set indoor temperature Ts by the remote controller 22, and this air flow value is set to the cooling / heating automatic operation mode. Automatic air volume control means that is set larger than in normal operation mode.

  [7] At the time of heating, if the detected temperature Ta of the indoor temperature sensor 13 is equal to or higher than a predetermined value (for example, 25 ° C.) and the detected temperature Tc of the heat exchanger temperature sensor 12 is equal to or higher than a predetermined value (for example, 30 ° C.), Control means for limiting the minimum air flow to a predetermined value or more.

  [8] During heating, if the detected temperature Tc of the heat exchanger temperature sensor 12 becomes equal to or higher than a predetermined value (for example, either 56 ° C. or 58 ° C.), a measure for suppressing the high pressure side pressure of the refrigeration cycle (compressor 1 High-pressure protection means for reducing the operating frequency of the motor or performing release control such as refrigerant bypass from the high-pressure side to the low-pressure side.

  [9] When the detected temperature Tc of the heat exchanger temperature sensor 12 is equal to or higher than a set value (for example, 40 ° C.), the predetermined value of the high-pressure protection means is set as high as 58 ° C., and the detected temperature Tc is set to the same set value (40 ° C.). Control means to set as low as 56 ° C when the temperature is lower.

  Next, the operation of the above configuration will be described with reference to the flowcharts of FIGS.

  In the normal operation mode (NO in step 101) and when the automatic air volume mode is not set (NO in step 102), the air volume of the indoor blower 7 is set according to a command from the remote controller 22 (step 103).

  In the normal operation mode (NO in step 101), the automatic air flow mode (YES in step 102), and during cooling (NO in step 104), the temperature difference ΔT (= Ta−Ts) and the normal cooling in FIG. The air volume of the indoor blower 7 is set by contrast with the air volume setting condition Bc (step 105).

  For example, if the temperature difference ΔT is + 1 ° C. or more, the large air volume H due to the high speed operation of the indoor blower motor 7, and if the temperature difference ΔT is less than + 1 ° C. and + 0.5 ° C. or more, the large air flow H occurs during the middle (up) speed operation of the indoor blower motor 7. When the air volume (high) M + and the temperature difference ΔT are less than + 0.5 ° C. and 0 ° C. or more, the indoor air blower motor 7 has a medium air volume M due to the medium speed operation and the temperature difference ΔT is less than 0 ° C. and −0.5 ° C. or more. Small air volume (high) L + due to low (up) speed operation of motor 7, small air volume L due to low speed operation of indoor fan motor 7 when temperature ΔT is less than -0.5 ° C, indoor fan motor when thermo-off (operation interrupted) 7 is set.

  In the normal operation mode (NO in step 101), in the automatic air volume mode (YES in step 102), and during heating (YES in step 104), the temperature difference ΔT and the normal heating air volume setting condition Bh in FIG. Is set, the air volume of the indoor blower 7 is set (step 106).

  For example, if the temperature difference ΔT is less than −1 ° C., the large air volume H due to the high speed operation of the indoor fan motor 7, and if the temperature difference ΔT is −1 ° C. or more and less than −0.5 ° C., the middle (upper) speed of the indoor fan motor 7 When the middle air volume (high) M + and the temperature difference ΔT due to the operation are −0.5 ° C. or more and less than 0 ° C., the middle air volume M and the temperature difference ΔT due to the medium speed operation of the indoor blower motor 7 are 0 ° C. or more and less than + 0.5 ° C. In this case, the small air volume (high) L + due to the low (upper) speed operation of the indoor blower motor 7 and the small air volume L due to the low speed operation of the indoor blower motor 7 when the temperature ΔT is + 0.5 ° C. or more, and the room when the thermo-off (operation is interrupted) A small air volume UL due to the ultra-low speed operation of the blower motor 7 is set.

  On the other hand, in the automatic cooling / heating operation mode (YES in step 101), in the automatic air volume mode (YES in step 107), and during cooling (NO in step 108), the temperature difference ΔT and the cooling air volume during automatic cooling / heating shown in FIG. The air volume of the indoor blower 7 is set by contrast with the set condition Ac (step 109).

  For example, if the temperature difference ΔT is + 1 ° C. or more, a large air volume (high) H + by the maximum speed operation of the indoor blower motor 7, and if the temperature difference ΔT is less than + 1 ° C. and more than + 0.5 ° C., the middle (upper) speed of the indoor blower motor 7 When the medium air flow (high) M + and the temperature difference ΔT due to the operation are less than + 0.5 ° C. and 0 ° C. or more, the medium air flow (high) M + due to the (up) speed operation of the indoor blower motor 7 and the temperature difference ΔT are less than 0 ° C. When the temperature is −0.5 ° C. or more, the medium air flow rate M due to the medium speed operation of the indoor blower motor 7 is set, and when the temperature ΔT is less than −0.5 ° C., the small air flow rate (high) L + due to the low (up) speed operation of the indoor blower motor 7 is set. Is done.

  In the automatic cooling / heating operation mode (YES in step 101), the automatic air volume mode (YES in step 107), and the heating time (YES in step 108), the temperature difference ΔT and the heating air flow rate setting condition in the automatic cooling / heating operation shown in FIG. The air volume of the indoor blower 7 is set by contrasting with Ah and further by comparing the detected temperature Tc of the heat exchanger temperature sensor 13 with the air volume setting condition C (step 110).

  For example, if the temperature difference ΔT is less than −1 ° C., a large air volume (high) H + due to the maximum speed operation of the indoor blower motor 7, and if the temperature difference ΔT is −1 ° C. or more and less than −0.5 ° C., Above) Medium air flow (high) M + due to speed operation and temperature difference ΔT of −0.5 ° C. or more and less than 0 ° C., medium air flow (high) M + and temperature difference ΔT due to (up) speed operation in indoor blower motor 7 When the temperature is equal to or higher than 0 ° C. and lower than + 0.5 ° C., the medium air flow rate M due to the medium speed operation of the indoor blower motor 7 is set, and when the temperature ΔT is + 0.5 ° C. or higher, the small air flow (high) L + due to the low speed operation of the indoor blower motor 7 is set. You.

  However, in this case, as for the large air volume (high) H + which is the maximum air volume value (when the temperature difference ΔT is less than −1 ° C.), as shown in FIG. If the detected temperature Tc is in the P zone where the detected temperature Tc is lower than 47 ° C., it is set to be one rank lower than the large air volume H while the detected temperature Tc is in the P zone where the detected temperature Tc is lower than 47 ° C.

  Then, at the time of cooling (NO in step 111), the indoor blower 7 is operated at the set air volume (YES in step 117).

  During heating (YES in step 111), the detected temperature Ta of the room temperature sensor 13 is 25 ° C. or more (YES in step 112), and the detected temperature Tc of the heat exchanger temperature sensor 13 is 30 ° C. or more (YES in step 113). If the set airflow for the indoor blower 7 is less than a predetermined value, for example, less than [weak wind (high) L +] (YES in step 114), the indoor blower 7 is forcibly operated with [weak wind (high) L +]. (YES in step 115). This air volume restriction is performed only for a predetermined time and once each time the operation is started.

  If the set airflow for the indoor blower 7 is equal to or more than [weak wind (high) L +] (NO in step 114), the indoor blower 7 is operated at the set airflow (YES in step 117).

  However, even if the detected temperature Ta of the indoor temperature sensor 13 is equal to or higher than 25 ° C. (YES in step 112), if the detected temperature Tc of the heat exchanger temperature sensor 13 is lower than 30 ° C. (NO in step 113), the indoor blower 7 sets the set air volume. (Step 117, YES).

  As in the case of starting heating (including resuming operation after thermo-off and resuming operation after defrosting), the detected temperature Ta of the room temperature sensor 13 is less than 25 ° C. (YES in step 112), and the heat exchanger temperature sensor 13 If the detected temperature Tc is less than 30 ° C. (NO in step 113), the standby state is set and the operation of the indoor blower 7 is suspended until the detected temperature Tc of the heat exchanger temperature sensor 13 reaches 30 ° C.

  By the way, the cooling air flow rate setting condition Bc in the normal state, the cooling air flow rate setting condition Ac in the automatic cooling / heating operation, the heating air flow setting condition Bh in the normal operation, and the heating air flow setting condition Ah in the automatic cooling / heating operation are set to the room temperature Ta. The difference ΔT from the room temperature Ts is divided into a plurality of zones, and the airflow value is assigned to each of these zones, and the airflow values of at least some of these zones are set to be larger in the cooling / heating automatic operation mode than in the normal operation mode. You have set. That is, the minimum airflow value in the cooling / heating automatic operation mode is set to be larger than the minimum airflow value in the normal operation mode. The maximum airflow value in the cooling / heating automatic operation mode is set to be larger than the maximum airflow value in the normal operation mode.

  As described above, while controlling the air volume of the indoor blower 7 in accordance with the temperature difference ΔT corresponding to the air conditioning load, the air volume value is set to be larger in the cooling / heating automatic operation mode than in the normal operation mode, whereby the cooling / heating automatic operation is performed. Even when the air-conditioning capacity (operating frequency of the compressor 1) is set to be small in order to perform the energy-saving operation in the mode, the reduced air-conditioning capacity can be compensated for by the increase in the air volume of the indoor blower 7, so that appropriate Room temperature control is possible.

  Further, in the air volume setting condition of the cooling / heating automatic operation mode, the amount of reduction of the air volume value is set to be smaller as the indoor temperature Ta approaches the set indoor temperature Ts, and the minimum air volume value is set to be larger than that in the normal operation mode. Therefore, the room temperature Ta can be quickly converged to the set room temperature Ts.

  Further, during heating in the cooling / heating automatic operation mode, the large air volume (high) H + which is the maximum air volume value is set as it is if the detection temperature Tc of the heat exchanger temperature sensor 13 is in the Q zone of 47 ° C. or higher. While the detected temperature Tc is in the P zone of less than 47 ° C., the large air volume H is changed and set to be one rank lower, so that the temperature of the air blown into the room can be maintained at an optimal predetermined temperature or higher.

  At the time of heating, when the indoor temperature Ta is as high as 25 ° C. or more and the heat exchanger temperature Tc is at least 30 ° C., if the air volume of the indoor blower 7 is small, the high-pressure side pressure of the refrigeration cycle rises abnormally. When the heat exchanger temperature Tc rises above a predetermined value (for example, either 56 ° C. or 58 ° C.), the high-pressure protection means (reducing the operating frequency of the compressor 1 or releasing control of the refrigerant bypass from the high-pressure side to the low-pressure side) is performed. It operates (step 120), and in the worst case, a high-pressure switch (not shown) is operated to stop the operation. Under such conditions, the minimum air flow of the indoor blower 7 is limited to a predetermined value or more. Therefore, it is possible to suppress an increase in the high pressure side pressure before the high pressure protection function is activated. Unnecessary stoppage of operation due to the operation of the high-voltage switch can be avoided, so that efficient air-conditioning without interruption is possible, and it is possible to contribute to an improvement in energy saving effect.

  In addition, by limiting the minimum air volume of the indoor blower 7 to a predetermined value or more, the followability of the rise in the heat exchanger temperature Tc to the rise in the high-pressure side pressure is improved, and the high-pressure protection function can be properly operated.

  In particular, when the heat exchanger temperature Tc is 40 ° C. or higher, the higher value of 58 ° C. is selected (YES in step 118, step 119) as the predetermined value which is the operating point of the high-pressure protection means. In a situation in which the rise in the heat exchanger temperature Tc cannot keep up with the rise in the high-pressure side pressure, for example, when the heating is started (including when the operation is restarted after the thermo-off and when the operation is restored after the defrosting), Since the lower 56 ° C. is selected (YES in step 118, step 120), the high-pressure protection function can be reliably activated even if the follow-up is slow, even if the high-pressure side pressure rises abnormally.

  The present invention is not limited to the above-described embodiment, and can be variously modified without changing the gist.

FIG. 2 is a block diagram of a control circuit according to one embodiment. The block diagram of the refrigeration cycle of the embodiment. The figure which looked at the cross section of the structure of the indoor unit of the embodiment from the side. The figure which looked at the cross section of the structure of the indoor unit of the embodiment from above. 4 is a flowchart for explaining the operation of the embodiment. The flowchart following FIG. The figure which shows the air volume setting condition at the time of cooling in the same Example. The figure which shows the air volume setting condition at the time of the heating in the same Example. The figure which shows the air volume setting condition at the time of the heating in the same Example.

Explanation of reference numerals

  DESCRIPTION OF SYMBOLS 1 ... Variable capacity compressor, 3 ... Outdoor heat exchanger, 5 ... Indoor heat exchanger, 7 ... Indoor blower, 12 ... Heat exchanger temperature sensor, 13 ... Indoor temperature sensor, 20 ... Indoor control part, 23 ... Speed control Circuit, 40 ... Outdoor control unit, 41 ... Inverter circuit.

Claims (4)

An air conditioner that includes a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an indoor blower having a variable air volume, and capable of cooling and heating.
An indoor temperature sensor for detecting the temperature of indoor air,
A heat exchanger temperature sensor for detecting the temperature of the indoor heat exchanger,
At the time of heating, when the detection temperature of the indoor temperature sensor is equal to or higher than a predetermined value, and when the detection temperature of the heat exchanger temperature sensor is equal to or higher than a predetermined value, a control unit that limits the minimum air flow of the indoor blower to a predetermined value or higher,
An air conditioner comprising: 2. The air conditioner according to claim 1, wherein the control unit performs the restriction for a predetermined time. 2. The air conditioner according to claim 1, wherein the control unit performs the restriction once each time the operation is started. Compressor, outdoor heat exchanger, equipped with a refrigeration cycle to connect the indoor heat exchanger and circulate the refrigerant, in an air conditioner capable of cooling and heating,
A heat exchanger temperature sensor for detecting the temperature of the indoor heat exchanger,
At the time of heating, when the temperature detected by the heat exchanger temperature sensor is equal to or higher than a predetermined value, high-pressure protection means for performing a measure for suppressing the high-pressure side pressure of the refrigeration cycle,
Control means for setting the predetermined value of the high-pressure protection means, when the detected temperature of the heat exchanger temperature sensor is less than a set value, than when the detected temperature is equal to or more than a set value;
An air conditioner comprising:

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